How to remove row if it has a NA value in one certain column

Question

My data called "dat":

A   B   C
NA  2   NA
1   2   3
1   NA  3
1   2   3

I want to be all rows to be removed if it has an NA in column B:

A   B   C
NA  2   NA
1   2   3
1   2   3

na.omit(dat) removes all rows with an NA not just the ones where the NA is in column B.

Also I'd like to know how to this for NA value in two columns.

I appreciate all advice!

Answer 1

The easiest solution is to use is.na():

df[!is.na(df$B), ]

which gives you:

   A B  C
1 NA 2 NA
2  1 2  3
4  1 2  3